[gnumeric] sstest: also test RANDTDIST.

[Morten Welinder <mortenw src gnome org>]

commit 964a7781e40723f44756c8efdac7809835c2239f
Author: Morten Welinder <terra gnome org>
Date:   Fri Mar 20 13:52:56 2015 -0400

    sstest: also test RANDTDIST.

 ChangeLog    |    1 +
 src/sstest.c |   68 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 68 insertions(+), 1 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index a597669..f38762e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,6 +9,7 @@
        (test_random_randlog): New test.
        (test_random_randdiscrete): New test.
        (test_random_randgamma): New test.
+       (test_random_randtdist): New test.
 
        * src/gnm-random.c (random_logarithmic): Fix.  See #746449.
 
diff --git a/src/sstest.c b/src/sstest.c
index a1ee5bd..db74054 100644
--- a/src/sstest.c
+++ b/src/sstest.c
@@ -1071,6 +1071,72 @@ test_random_randgamma (int N)
 }
 
 static void
+test_random_randtdist (int N)
+{
+       gnm_float mean, var, skew, kurt;
+       gnm_float *vals;
+       gboolean ok;
+       gnm_float param_df = gnm_floor (1 / (0.01 + gnm_pow (random_01 (), 6)));
+       gnm_float mean_target = 0;
+       gnm_float var_target = param_df > 2 ? param_df / (param_df - 2) : gnm_nan;
+       gnm_float skew_target = param_df > 3 ? 0 : gnm_nan;
+       gnm_float kurt_target = param_df > 4 ? 6 / (param_df - 4) : gnm_nan;
+       char *expr;
+       gnm_float T;
+       int i;
+
+       expr = g_strdup_printf ("=RANDTDIST(%.0" GNM_FORMAT_f ")", param_df);
+       vals = test_random_1 (N, expr, &mean, &var, &skew, &kurt);
+       g_free (expr);
+
+       ok = TRUE;
+       for (i = 0; i < N; i++) {
+               gnm_float r = vals[i];
+               if (!(gnm_finite (r))) {
+                       g_printerr ("Range failure.\n");
+                       ok = FALSE;
+                       break;
+               }
+       }
+       g_free (vals);
+
+       T = mean_target;
+       g_printerr ("Expected mean: %.10" GNM_FORMAT_g "\n", T);
+       if (gnm_finite (var_target) && !(gnm_abs (mean - T) < 3 * gnm_sqrt (var_target / N))) {
+               g_printerr ("Mean failure.\n");
+               ok = FALSE;
+       }
+
+       T = var_target;
+       g_printerr ("Expected var: %.10" GNM_FORMAT_g "\n", T);
+       if (!(var >= 0 && gnm_finite (var))) {
+               /* That is a very simplistic test! */
+               g_printerr ("Var failure.\n");
+               ok = FALSE;
+       }
+
+       T = skew_target;
+       g_printerr ("Expected skew: %.10" GNM_FORMAT_g "\n", T);
+       if (!gnm_finite (skew)) {
+               /* That is a very simplistic test! */
+               g_printerr ("Skew failure.\n");
+               ok = FALSE;
+       }
+
+       T = kurt_target;
+       g_printerr ("Expected kurt: %.10" GNM_FORMAT_g "\n", T);
+       if (!(kurt >= -3 && gnm_finite (kurt))) {
+               /* That is a very simplistic test! */
+               g_printerr ("Kurt failure.\n");
+               ok = FALSE;
+       }
+
+       if (ok)
+               g_printerr ("OK\n");
+       g_printerr ("\n");
+}
+
+static void
 test_random_randbinom (int N)
 {
        gnm_float mean, var, skew, kurt;
@@ -1497,6 +1563,7 @@ test_random (void)
        test_random_randsnorm (High_N);
        test_random_randexp (N);
        test_random_randgamma (N);
+       test_random_randtdist (N);
 
        test_random_randbernoulli (N);
        test_random_randdiscrete (N);
@@ -1525,7 +1592,6 @@ test_random (void)
        test_random_randrayleigh (N);
        test_random_randrayleightail (N);
        test_random_randstdist (N);
-       test_random_randtdist (N);
        test_random_randuniform (N);
        test_random_randweibull (N);
 #endif